Forum Moderators: open
And what do you like to know about alpha or beta websites?
If you're asking when to submit:
Finish some version that makes sense (to users, and to SE's). Submit it, or link it from an already indexed site. Then enlarge it.
Don't submit some alpha or beta version if you're not sure that domain, the main structure (esp. internal linking structure, keyword-relevant stuff, and - maybe - incoming links) for the most part will persist.
My 2 c.